Is that even possible? last I heard the draws were every 60. What scenario lets a back to back banner happen outside of Super Rares?

Kage banners are every 60 apparently so Free Drawing Mei or Jigo in Tendo if the free draw is your 60th isn't unusual if I'm understanding you right, but it is lucky given the fact Mei is arguably the best character in Kage Treasure (She really should have been a Super Rare instead of Raikage)

The only thing I can think of about the algorithms is that every day or even every hour, I'm not sure what, the likelihood of "Which" banner you get changes, maybe it's a Mei Day, maybe a Chojuro day.

What makes me think this is true is that I've seen quite a few times people drawing the Same banner Ninja close together, multiple people drawing Chojuro within like an hour of eachother, in one case a guy on my server got Mei on his alt in a Free draw and immediately pulled for her and got her on his Main account as the next banner.

Summon rebate first drew my attention to this idea when I watched 2 or 3 people Draw Fukurokumaru in about an hour and as another person said they were about to do the rebate I said "You're going to get Fukurokumaru" and sure enough right out the gate that's what they got.

All of this is just speculation but I really feel like there is something going on here that makes different banner Ninjas more likely to be the one you get when you're due for a banner Ninja depending on when you do it.

This would also explain situations where someone dumps 800+ scrolls into Kage and they manage to get a Super Rare before they get the Mei they had been after for so long.